Sarah,
Yes, it happens to us all. I can be doing good making small steps, and bam one day nothing, and get all down. But I have to keep telling myself that I am my own worst critic or enemy. I cannot beat myself up over one step back. Nor can I let myself become the disorder, I may have it, but I am not it. I usually gets bout of depression around my menstrual cycle, this could be something you are experiencing too. As far as headaches, are you abruptly stopping caffine? I know that cause me headaches, and I had to taper myself off caffine, and if I dont eat properly, skipping meals, etc., I will also get headaches. And remember, you might be feel some effects from the medicine, but it takes sometimes 6 weeks to reach full potential, dont give up hope!
Trish